# and 一假则假 左假全假
# or 一真则真 左真右假
# not 逻辑取反
# 短路求值

a = 10
b = 20
c = 30

print(a < b < c)
#等价
print(a < b and b < c)
print(a < b and b > c)

print(a < b or b > c)

print(not a < b)
#未抛异常,又测未处理

print(a > b and 10 / 0 == 1)
print(a > b or 10 / 0 == 1)